Generator Low Voltage

[gator87]

While attempting to perform our monthly generator exercise under load on our 2017 3010DS, the generator started properly but did not trip the automatic transfer switch at the 30 second mark. We shut down the generator and restarted with same results. Shore power was disconnected both times. After reading several threads on the ATS, I went under the back bed and tested voltage on the ATS lugs. On shore power, it read 119V on both the shore leg and house leg. Disconnected shore power and all voltage readings were 0. Started generator, waited 30 seconds and tested voltage. Read 2.7V on generator lug, 0 on house feed. Puzzled, I checked breaker at generator and it was on. Cycled breaker off and on, same low voltage at ATS. Pulled generator breaker housing out and test voltage on the breaker - 123V on both sides of breaker. OK, figured problem was between generator and ATS. Traced power feed out of generator and into first storage compartment next to generator to check junction box. Junction takes aluminum stranded wires from generator and converts to solid copper wires to ATS. Inside box, I found my problem. Wire nut on white wire was melted - see picture. I cut both white wires, reconnected with shorter bare end on solid wire, added new wire nut, insulated tape covered by electrical tape. Made same repair to black wire in case. Ground wire was ok. Put junction box back together and made sure wire nuts were not wedged against the box. Turn on generator, watch ATS and whallah! Back in business. Ran AC for 1 hour to make sure. Replaced all covers on boxes. Off to Cape Cod on Saturday for a week of boondocking. Life is good.
Thanks to all you who post questions & answers on this forum. It has helped me mucho times and I hope this helps someone too.

[Garrette]

Thank you, I will be checking mine this week.

[tom39]

When making a connection using copper and aluminum wiring, there are measures you want to take to insure longevity of the connection and avoid issues down the road. The use of the right connector will help with this.
If you hadn't done so already, I would suggest that you use a wire nut specifically designed for this application.

https://www.lowes.com/pd/ideal-twist...RoCX7MQAvD_BwE

Hope it helps
Tom

[DaGrinch]

Originally Posted by Garrette

Thank you, I will be checking mine this week.

DITTO!

[CHICKDOE]

i'm amazed they use aluminum wire to start with. we had it in our old house and it caused problems!

[CHICKDOE]

i'm amazed they use aluminum wire to start with. we had it in our old house and it causes problems. what is it, may a 5 foot run? can you replace it with copper. if nothing else use the special aluminum to copper wire nuts that were mentioned earlier. there are other type of these connectors. then there is the generator connection where the aluminum connects to the generator terminals. the problem is that the aluminum gets brittle and cracks when subject to vibrations. then it fails like your did or it can spark across the crack. and the rv probably is subject to more vibration than our old house received, earthquakes included.

[formerFR]

Aluminum wiring has it's positives and negatives, just like copper, and both are certainly useful in their own right - Aluminum is also what you mainly see in all of the overhead and transmission wiring to your home, even down into your Main Panel - it's not copper.

Copper does not expand as much as AL when heated, so AL needs a better overall 'connection' or the expansion could create a 'loose' connection, which is probably what the OP experienced in this junction box. Having said that, we've probably all experienced the same issue with copper wire, so it's not the 'wire' type that's the issue, but the connection. 'Heat' causes both to expand and therefore will test any 'not so tight' connection.